1. Field of the Invention
The present invention generally relates to a cleaning apparatus and a cleaning method which is used in an electrophotographic type image forming apparatus such as a copier or a laser printer to remove deposits such as dust or an extraneous substance attached or fixed on a component having a complicated shape by using a solid cleaning medium. More specifically, the present invention provides an effective technique to efficiently clean a long and thin object to be cleaned.
2. Description of the Related Art
To realize a society with an environmentally-sound material cycle, business equipment manufacturers of copiers, facsimile machines, or printers actively practice recycling activities. In the activities, they collect used products or various units from users, and then disassemble, clean, and reassemble them so as to be used as components or a resin material. In order to reuse components used in these products or various units, a step of removing toner, which is minute particles, attached on the disassembled components or units has been required. Thus, it has been a great challenge to reduce cost and environmental load.
For the cleaning, in general, a wet-type cleaning method has been often employed, such as an ultrasonic wave cleaning method to dip the components or units in a water tank and apply ultrasonic waves, and a shower cleaning method to direct a high speed stream of water to an object to be cleaned by using a nozzle. When such a wet-type cleaning method is used to clean the components or units on which a stain of toner and the like are attached, processing of a waste solution including the toner and the like and a drying process after the cleaning consume a large amount of energy and are very costly.
On the other hand, a dry-type cleaning method using an air blow does not exhibit a sufficient cleaning performance with respect to toner and the like that have a strong attaching force. Therefore, a post-step of wiping with a waste cloth by hand and the like have been required. In this manner, cleaning has been one of the bottleneck steps in reusing and recycling the products.
To solve the above-described problems, a cleaning apparatus disclosed in Patent Document 1 flows air in a cleaning tank, causing lightweight, solid, and easy-to-fly cleaning media to fly in the cleaning tank, so that the cleaning media continuously contact an object to be cleaned, and a deposit attached on the object to be cleaned (attached dust, powder, or a stain fixed in a film state on the object to be cleaned) is separated without using water. In particular, by using cleaning media in flexible thin pieces, a cleaning performance equivalent to or more than the ultrasonic wave cleaning method can be exhibited even with a small amount of the cleaning media.
Moreover, there has been known a method to clean a whole surface of the object to be cleaned without using a cleaning tank for storing the object to be cleaned. By this method, the whole surface of the object to be cleaned is cleaned by removing an extraneous substance in a small spot area of the object by using a blast gun and the like and scanning a blowing position of the blast gun over the object to be cleaned. For example, a cleaning apparatus disclosed in Patent Document 2 causes flying substances formed of a sponge or a rubber sphere having a hollow center, which have a diameter of about 10 to 30 mm, to fly in a cone shaped housing by using compressed air, so as to collide with and clean a spot area of the object to be cleaned.    [Patent Document 1] Japanese Patent Application Publication No. 2007-29945    [Patent Document 2] Japanese Utility Model Registration No. 2515833
The dry-type cleaning apparatus as disclosed in Patent Document 1 employs a method to put the object to be cleaned in the cleaning tank so as to be collided with cleaning media. Therefore, a cleaning tank that has a volume equal to or more than the size of the object to be cleaned has been required to be prepared. Because of this, it has been difficult to clean a large object to be cleaned. Moreover, when various components in different sizes are to be cleaned by one cleaning apparatus, a cleaning tank and process conditions have had to be adjusted for the largest component. In this case, when a small object to be cleaned is put in the cleaning tank, it is inefficient since flying cleaning media which do not contribute to cleaning are increased. Further, since an optimum cleaning condition changes depending on the size of the object to be cleaned, there have been problems in that it has been troublesome to adjust the condition in cleaning various kinds of objects, and quality of the cleaning is not consistent.
In the cleaning method disclosed in Patent Document 2, the inside of the housing has a positive pressure. Therefore, it has been difficult to prevent leakage of the small and flexible flying media. Moreover, this cleaning method is more suitable for cleaning a plane surface. In the case of cleaning an object having a three-dimensionally complicated shape, there is usually a space formed between the housing and the object to be cleaned. Thus, it has been difficult to perform cleaning without leaking the cleaning medium. When the cleaning medium is leaked, there have been problems in that an operation environment is polluted, and at the same time, the number of cleaning media flying in the housing is decreased and that the cleaning performance is degraded.
According to at least one embodiment, the present invention is made to improve such disadvantages and provides a cleaning apparatus and a cleaning method which can efficiently clean even an object to be cleaned having a complicated surface shape, by causing cleaning media to fly in a cleaning tank without stagnation as well as by downsizing the volume of the cleaning tank.
Further, according to at least one embodiment, the present invention is made to obtain a consistent cleaning performance by effectively using cleaning media by quickly collecting the cleaning media into the cleaning tank when the cleaning media leak from the space in the cleaning tank where the cleaning medium fly.